The evolution of mobile telecommunication systems has brought about numerous offerings in the form of subscriber services. Early telecommunication systems, for example the advanced mobile phone system, were analog cellular systems and, consequently, were limited to providing basic voice services. However, modern telecommunication systems provide digital communications and are no longer confined to strictly voice services. Various data services are currently offered to cellular subscribers and include text messaging, and email as well as cellular Internet services presently being deployed. For example, general packet radio services (GPRS) were introduced in the Global System for Mobile communications (GSM) to more effectively utilize the radio spectrum for providing data oriented services. GPRS is a packet switched, rather than a circuit switched, data service and generally is more efficient than circuit switched data services because of deallocations of radio resources made during idle periods in a data communication session.
Various control nodes are typically distributed throughout the mobile telecommunication system. For example, mobile service switching centers (MSCs) are responsible for performing control and supervisory functions related to mobile connections to circuit switched networks, for example the public switched telephone network (PSTN). A gateway GPRS support node (GGSN) is typically accessed for connecting to a packet data network to access general packet radio services such as wireless Internet services. One or more Serving GPRS Support Nodes (SGSN) are included within the mobile telecommunication system for providing the mobile terminal access to the GPRS services, for example administering packet data protocol (PDP) sessions as well as performing managerial functions such as mobile terminal authentication, identification and IMEI interrogations. Thus, the GGSN provides an interface for the mobile telecommunications system to the data network while the SGSNs enable the mobile terminal to communicate with the GGSN and thus the packet data network over the traditional mobile telecommunication system infrastructures.
Voice and data mobile telecommunication services are provided over an air interface between the mobile terminal and the mobile telecommunication system. One or more base transceiver stations (BTSs) engage an active mobile terminal over an air interface. The BTSs are controlled and supervised by base station controllers (BSCs). The BSCs are, in turn, managed by MSCs. Each BSC can control multiple BTSs. Similarly, each MSC can manage multiple BSCs. Each BSC and the BTSs controlled thereby comprise a base station subsystem (BSS). The MSC and associated managerial hardware and software comprise a switching subsystem (SS).
Mobile terminal voice service subscriptions typically levy a fee for a given quantity of network access time. Additional tariffs may then be implemented when the subscriber exceeds the allotted access time. Often, the network operators assign a home area within the mobile telecommunications network in which the access time may be used. When a subscriber travels outside the home area, additional tariffs may be levied, typically in the form of higher tariffs per unit of access time.
Network operators are finding a growing demand for data services such as GPRS. Various usage-based tariff schemes have been implemented for applying toll charges based on the volume of data usage by a mobile terminal. Much like common cellular voice subscription services that charge a flat fee for a particular number of minutes of cellular access, data usage tariffs commonly have fee structures based on the amount of data transmitted to or from the mobile terminal. A mobility call detail record (M-CDR) is activated whenever a mobile terminal attaches to a mobile telecommunication system (MTS). Containers within the M-CDR monitor the location of the mobile terminal within the network. The M-CDR is typically maintained as long as the mobile terminal is attached to the MTS and remains in a specific coverage area of the network, for example a location area that is limited to the geographic service area of a single SGSN.
A Serving GPRS Support Node call detail record (S-CDR) is generally implemented for monitoring the traffic volume to and from a mobile terminal. A S-CDR is opened in a SGSN whenever an attached mobile terminal initiates a data session, for example a packet data protocol session. In an active session, the mobile terminal is able to transfer and receive payload data on a respective uplink and downlink with a packet data network, whereas when the mobile terminal is only attached, the mobile terminal is in a state designated as ‘stand-by’. The S-CDR creates a traffic volume container that monitors the volume of data transfers made from the mobile terminal to the data network on the uplink and the volume of data transfers made to the mobile terminal on the downlink. When the mobile deactivates, or when the mobile terminal roams into a cell having data services provided by another SGSN, the S-CDR is closed. The S-CDR can then be retrieved from the SGSN by a charging gateway function (CGF) and processed to levy appropriate fees to the subscriber of the mobile terminal.
Network operators have devised various ‘triggers’ for enabling variations in the tariffs associated with data transfers to a mobile terminal. Tariff time change triggers can be executed in a SGSN for enabling variations in the billing fees associated with mobile data services according to, for example, the time of day or the day of week that the data transfers are made. A tariff time change trigger is typically invoked by a system clock in the SGSN and, upon execution thereof, causes any open traffic volume containers in a S-CDR to be closed. A new traffic volume container is opened within the S-CDR and the traffic volume is then monitored and counted in the newly opened traffic volume container. The traffic volume containers generally include timestamps, along with other information, for facilitating proper billing when the S-CDR is processed by the operator's billing system.
Partial record triggers may also be implemented to guard against loss of data, for example a failure in a SGSN that causes a loss of S-CDRs or M-CDRs, that would adversely effect the network operator's ability to implement an accurate billing to the mobile subscriber's effected by the lost S-CDRs or M-CDRs. A partial record S-CDR is created by clearing, or zeroing, the contents of the traffic volume containers in an open S-CDR after reporting these contents to an appropriate management node, for example a CGF. Accumulation of further traffic volume counts are then made from the zeroed traffic volume container in the S-CDR. To facilitate accurate billing to a subscriber having traffic volume counts accumulated over multiple partial records, a record sequence number may be stored in a field of the S-CDR. Each time a partial record is made, the record sequence number in the S-CDR is incremented. The CGF, or similar facility, can later combine the partial records according to the record sequence numbers for providing an appropriate billing to the subscriber associated therewith. Common S-CDR partial record triggers include duration triggers, traffic volume triggers, and triggers based on the number of traffic volume containers in a S-CDR. Other S-CDR partial record triggers may be implemented by management intervention. Similar M-CDR partial record triggers may be likewise implemented.
Different mobile subscribers may have different preferences with regard to the quality of service provisioned by the SGSN when accessing a data network. Quality of Service (QoS) triggers have been implemented to allow variations in billing fees associated with the quality of service a mobile terminal is provided with when accessing a data network. For example, the network operator may impose a higher tariff when a mobile terminal accesses a data network on full-rate equipment rather than half-rate equipment. A QoS trigger facilitates quality of service tariff changes during an active session with data network by closing an open traffic volume container in a S-CDR when a QoS criteria threshold is met during the data session. For example, during an active session, full-rate channels in a BTS serving the mobile terminal may become unavailable. When a mobile terminal switches to a full-rate channel from a half-rate channel, a QoS trigger may close a current traffic volume container and open another traffic volume container. The network operator then may impose a higher tariff when a user accesses a data network over a full-rate channel.
Heretofore, however, a network operator has not had the ability to impose variations in tariffs assigned to data transfer volumes based on the location of a mobile terminal. As a mobile terminal roams throughout a network, any S-CDRs that are opened may maintain open traffic volume containers therein regardless of the geographic coverage area provided by a SGSN that the mobile terminal migrates to.
Therefore, it may be seen from the foregoing that a solution for location based billing of data services in a mobile telecommunication system is desired.